Hazelnut (Corylus avellana L.) is one of the most popular nuts worldwide and plays an important role in human nutrition and health, because it is a rich source of fat, protein, carbohydrate, dietary fibre, minerals vitamins, phytosterols and antioxidant phenols (1). Due to their organoleptic characteristics, hazelnut is also used as an ingredient in a variety of processed foods including confectionary, chocolates and desserts. More frequently, the kernels are roasted in order to improve the aroma, texture and taste of products. The thermal treatment of nuts inevitably leads to chemical changes mainly determined by the nut composition and by the temperature and extent of heating Because of that, the objective of this study was to evaluate the influence of different roasting intensities on the physical-chemical (activity water, moisture and colour) and biochemical (volatile compounds, tocopherols, phenolic content and antioxidative activity) properties of Polish hazelnuts (cv. Kataloński). According to the range commonly used in the hazelnut industry, nuts were roasted at six specific temperature/time conditions: 130 °C/40 min, 130 °C/50 min, 130 °C/60 min, 160 °C/20 min, 160 °C/25 min, 160 °C/30 min. As expected, hazelnuts roasted at 160° C showed a darker color and a lower water activity and moisture than samples roasted at 130 °C. Compared to raw hazelnuts, the phenolic content increased in all roasted samples, although with a more concentration in nuts roasted at 160° C. The antioxidant activity showed an initial decrease after roasting, reaching than a maximum in samples roasted at 130 °C/60 min and 160 °C/30 min. Finally roasting contributed to release a lot of volatile compounds that belong to ketones, aldehydes, pyrazines, furans and other compounds. The different roasting conditions led to several aroma modification, in fact in raw hazelnuts were identified just only 22 compounds, whereas in samples roasted at 130° C and 160° C were found 79 and 102 volatiles,respectively . Among these, the 5-methyl-(E)-2-hepten-4-one (filbertone), which is considered the primary odorant of roasted hazelnut, was identified in all roasted samples.
Study of the effects of different roasting conditions on physical-chemical and biochemical properties of polish hazelnuts (Corylus avellana L. var. Kataloński)
MARZOCCHI, SILVIA;PASINI, FEDERICA;VERARDO, VITO;ROMANI, SANTINA;CABONI, MARIA
2015
Abstract
Hazelnut (Corylus avellana L.) is one of the most popular nuts worldwide and plays an important role in human nutrition and health, because it is a rich source of fat, protein, carbohydrate, dietary fibre, minerals vitamins, phytosterols and antioxidant phenols (1). Due to their organoleptic characteristics, hazelnut is also used as an ingredient in a variety of processed foods including confectionary, chocolates and desserts. More frequently, the kernels are roasted in order to improve the aroma, texture and taste of products. The thermal treatment of nuts inevitably leads to chemical changes mainly determined by the nut composition and by the temperature and extent of heating Because of that, the objective of this study was to evaluate the influence of different roasting intensities on the physical-chemical (activity water, moisture and colour) and biochemical (volatile compounds, tocopherols, phenolic content and antioxidative activity) properties of Polish hazelnuts (cv. Kataloński). According to the range commonly used in the hazelnut industry, nuts were roasted at six specific temperature/time conditions: 130 °C/40 min, 130 °C/50 min, 130 °C/60 min, 160 °C/20 min, 160 °C/25 min, 160 °C/30 min. As expected, hazelnuts roasted at 160° C showed a darker color and a lower water activity and moisture than samples roasted at 130 °C. Compared to raw hazelnuts, the phenolic content increased in all roasted samples, although with a more concentration in nuts roasted at 160° C. The antioxidant activity showed an initial decrease after roasting, reaching than a maximum in samples roasted at 130 °C/60 min and 160 °C/30 min. Finally roasting contributed to release a lot of volatile compounds that belong to ketones, aldehydes, pyrazines, furans and other compounds. The different roasting conditions led to several aroma modification, in fact in raw hazelnuts were identified just only 22 compounds, whereas in samples roasted at 130° C and 160° C were found 79 and 102 volatiles,respectively . Among these, the 5-methyl-(E)-2-hepten-4-one (filbertone), which is considered the primary odorant of roasted hazelnut, was identified in all roasted samples.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
